So far, it's just been done in a laboratory dish and in rat brains. But if this can be done in human brains and with human cells, it may become a new treatment for Parkinson's disease.

Lorraine Iacovitti, PhD, professor of neurology at Thomas Jefferson University Medical College in Philadelphia, presented her report at the Society for Neuroscience meeting in Orlando this week.

In previous work with rats, Iacovitti and colleagues showed that transplanted nerve stem cells could develop into nerve cells that produced tyrosine hydroxylase, the enzyme needed to make dopamine.

To see if this worked with human nerve cells, Iacovitti grew brain stem cells in a laboratory dish. Using a mix of human growth hormones and nutrients, the researchers found they could coax about 25% of the stem cells to make tyrosine hydroxylase in the dish.

This proves that stem cells have the capacity to manufacture dopamine. In fact, when they removed the growth factor cocktail, the cells continued to produce the enzyme for five more days, Iacovitti says in her report.

They hope to be able to develop this as a treatment for Parkinson's disease in people, Iacovitti says in a news release. -->